Time-Sensitive Networking (TSN) is a set of IEEE standards designed to provide deterministic and low-latency communication over Ethernet networks. As industries increasingly adopt complex cyber-physical systems, TSN emerges as a key enabler for real-time validation and Hardware-in-the-Loop (HIL) testing. This paper explores the role of TSN in enhancing the fidelity, scalability, and reliability of validation and HIL environments, particularly in automotive and industrial domains.